‘I HATE you!” she shrieked, pulling the hair of a girl who writhed in pain.Scenes from a reformatory? Outtakes from “Girls Behind Bars”?

Nope. Just a class at Camp Broadway, where kids with stars in their eyes learn the tricks of the stage.

Now in its fifth season, it’s a chance for aspiring Sarah Bernhardts ages 10 to 17 (and the odd John Barrymore wannabe) to learn from the pros, for $850 for the week.

This year’s season kicked off Monday with a lesson in stage makeup. Since then, the campers have lunched with the stars of “The Music Man,” seen “Kiss Me, Kate,” brushed up their disco with “Saturday Night Fever” dancers and swung with the cast of “Swing.”

Come tomorrow, the camp concludes with a “gypsy challenge” – performances by teams named after producers: the Nederlanders, Shuberts, Jujamcyns and Dodgers.

It’s enough to make Andy Hardy types go weak in the knees – that is, the few Andy Hardy types who signed up. Only 15 of Camp Broadway’s 80 participants this summer are male – and it was an all-female group that turned out for the stage combat class with David DeBesse.

Hair-pulling was only part of it.

According to DeBesse, a handsome actor with 12 years of fight directing under his belt (catch him in the upcoming “Hamlet” with Campbell Scott), “stage combat” consists of everything from taking a fall to punching – “and how to do it safely.”

“Rule No. 1,” he said: “None of this should ever hurt.”

While practicing “the barrel,” an exercise in push-pull – and trusting one’s partner – Mandy Richichi and Melissa Monteleone grabbed each other’s wrists and bounded wildly across the room, a look of unscripted pain on their faces.

“It’s too hard!” cried Mandy, 14. “The jewelry!” And she pushed her power bracelets all the way up her arm. Then they barreled across the room again, bumping into other partners like random molecules.

After the hair-pulling came another important lesson: How to fake a punch.

“The first rule of stage combat: eye contact,” DeBesse said, and showed how actors telegraph their punches before winding up and punching air, then smacking their own bodies to make the sound.

Note to the punchees: “Your chin’s the first thing that goes back.” He mimed being punched with such authority that several girls gasped.

“Remember,” DeBesse said, “the more violent the scene, the more we have to trust our partner.”

The trick to simulating a choke? Duck your head to hide the fact that there’s no pressure being applied.

“Not a lot of kids get to do this,” said 15-year-old Kacie Sullivan happily.